Normalizing Expectations and the Physiology of Infant Sleep

Many parents, especially at the beginning of parenthood, hope their baby will sleep through the night after just a few months. This expectation, influenced by social, cultural, and commercial models, often clashes with the biological reality of infant development. Frequent night wakings are not a sign that something is wrong — they are a normal part of a baby’s neurological and emotional growth.

From an evolutionary perspective, night wakings serve an adaptive purpose. Humans, compared to other species, are born in a very immature state — a concept known as the theory of exterogestation — and their survival depends heavily on constant adult contact. Waking frequently allows the baby to maintain that bond, feed, regulate body temperature, and receive emotional comfort. Rather than being inconvenient, this is a protective trait of our species.

But that’s not all. If we look at the physiology and maturation of sleep, we see:

Shorter Sleep Cycles

In the first months of life, babies’ sleep cycles last between 45 and 60 minutes. At the end of each cycle, it’s normal for them to briefly wake up. These micro-wakings are part of an under-construction sleep architecture. Not all babies can fall back asleep on their own yet — sleep self-regulation is a skill that develops over time. So, if your baby needs you to fall asleep again, don’t worry — it’s completely normal!

Infant Sleep Stages

Unlike adults, who go through five defined sleep stages, newborns only experience two: active sleep (similar to adult REM) and quiet sleep (like deep sleep in adults). From around six months, sleep begins to resemble adult sleep more, but it can take years for sleep patterns to fully mature.

Night Sleep Consolidation

The ability to sleep for longer stretches at night develops gradually and at different speeds for each baby. Long-term studies show that it’s entirely normal for many children to wake up during the night until age 2 or even 3. This doesn’t mean there’s a problem.

A baby’s brain is constantly evolving in the early years. Sleep, especially REM phases, plays a vital role in consolidating learning, reinforcing memory, and regulating emotions. The need to sleep a lot — even if in fragmented chunks — is directly related to this maturation process.

Sleep and Emotional Regulation

We cannot separate sleep from emotional regulation. When a baby cries at night, it’s because they seek connection, soothing, and comfort. Responding to these needs with presence and calm not only avoids creating “bad habits,” but is essential to developing secure attachment — which, in turn, improves sleep quality in the long run.

Factors That Can Affect Your Baby’s Sleep:

Individual Temperament

Every baby has their own temperament — some are more sensitive to stimuli, others more adaptable. These differences mean some babies fall asleep more easily than others. It’s not about doing things right or wrong, but about recognizing each child’s uniqueness.

Illnesses, Developmental Milestones, and Regressions

During the first year, sleep “regressions” are often linked to milestones like crawling, speaking, or separation anxiety. Things like teething or common illnesses can also temporarily disrupt sleep.

Physical and Emotional Environment

An overstimulating, noisy, or unpredictable environment can impact sleep quality. Likewise, family stress, changes in routine, or caregiver anxiety play a significant role.

The Role of Family and Society in Shaping Expectations

Many parents feel like they’re failing if their baby doesn’t sleep through the night. This pressure often comes from unrealistic social expectations and a parenting model that overvalues early independence. Rethinking these beliefs and understanding that dependence is not a problem — but a legitimate need — helps parents approach this stage with more calm and confidence.

So, How Can You Support Sleep Without Training It?

It’s not necessary to “train” your baby to sleep. What babies truly need is consistent support and growing emotional autonomy.

Respectful and supportive strategies include:

• Creating calm and predictable bedtime routines
• Setting regular, but flexible, schedules
• Sleeping near your baby (safe co-sleeping or room-sharing)
• Offering comfort and emotional presence during wake-ups
• Adjusting expectations based on your baby’s age and needs

Expecting a baby to sleep through the night in the early months (or even years) is not only unrealistic — it also goes against everything we know about healthy biological and emotional development.

Recognizing that night wakings are normal, physiological, and often necessary is a crucial step toward more respectful, connected, and guilt-free parenting.

When we adjust our expectations, we reduce our own stress and help build a strong foundation for secure attachment, emotional well-being, and healthy development for our children.